In recent years, there has been schemed an aggregation business of aggregating electric power generated by a plurality of photovoltaic power generation facilities and supplying the power to consumers. An aggregation operator or aggregation entrepreneur (below, it is called aggregator) needs to evaluate the photovoltaic power generation plant with which the aggregator makes a contract for buying the power in order to increase profitability of the aggregation business. There has been conventionally proposed a method of evaluating the photovoltaic power generation plant on the basis of an amount of solar radiation in the photovoltaic power generation plant depending on weather data in the past and a facility capacity of the photovoltaic power generation plant.
It is essential for increasing profitability of the aggregation business not only to increase total generated energies to be aggregated but also to enhance utilization of predicting the total generated energy, i.e., to reduce a predictive error of the total generated energy. This is because when an error occurs in the total generated energy actually supplied by the aggregator against, e.g., a power generation schedule presented (or submitted) beforehand by the aggregator, it involves paying settlement money, resulting in a drop in profitability.
Accordingly, in the evaluation of the photovoltaic power generation plant, it requires to evaluate a generated energy of the photovoltaic power generation plant and also evaluate a predictive error of the total generated energy in case that the aggregator makes the contract with the photovoltaic power generation plant. However, it is difficult for the conventional evaluation method to evaluate the predictive error of the total generated energy.